Knit tubular fabric,method and apparatus for making the same

ABSTRACT

A CIRCULAR KNITTING MACHINE HAVING FOUR FEEDS, A PAIR OF YARN GUIDES FOR EACH FEED, FOR FEEDING A PAIR OF SEPARATED YARNS AT SAID FEED, MEANS CAUSING ALTERNATE NEEDLES TO PASS BETWEEN THE YARNS OF EACH PAIR OF YARN GUIDES AND CAUSING INTERMEDIATE NEEDLES TO ENGAGE AND KNIT SAID YARNS TO FORM A DOUBLE YARN STITCH, SAID ALTERNATE NEEDLES CASTING OFF, UN-KNIT, THE YARN FROM A FIRST YARN OF ANOTHER PAIR OF YARN GUIDES AND FLOATING THE SECOND YARN OF ANOTHER PAIR PAIR OF YARN GUIDES.

Feb. 23 1971 FMGENBAUM ET AL; 3,564,871 KNIT TUBULAR FABRIC. METHOD 'A'ND APPARATUS FOR MAKING THE SAME Filed April 4. 1968 1 4 Sheets-Sheet 1 V INVENTORS.

. ROY armceumum ATTORNEY.

Feb. 23-, 1971 FMGENBAUM ETAL 3,564,871

KNIT TUBULAR FABRIC. METHOD AND APPARATUS FOR MAKING THE SAME Filed April 4, 1968 4 Sheets-Sheet 2 v3 TOP OF A 5PLL17/M; Y2 Y2 Y8 NEEDLE JTEM Y2 w a n n I q \T yz YILGY Y j ["27" [Y8 2" VIM {IX \X Y6}: y7 78:: ya Yg Q yr Y7 Y7 Y7 FEED -5 VFEED Fl -L SHORT 3 ONE 32 4 NEEDLES NEEDLES n a 29 so 2 6 INVENTORS ROY D. FAIGENBAUM JOHN GPECZIN BY M G7 Y7 ATTORNEYS Fe. 23, 1971 R FAlGENBAUm ETAL 1 3,564,871

KNIT TUBULAR FABRIC. METHOD AND APPARATUS FOR MAKING THE SAME Filed April 4, 1968 4 Sheets-Sheet s SPL/TT/A/G NEEDLE STEM n r- 0F YARNS Y6 all; r ys c '3 V3 y; ji z Y5 )5876 V6 1 N Y a 5&3 A 7 Yz/ Y4 Y4 Y4/ y4/ y4 Y4 Y1 Y3 Y v5 v3 6 Y2 Y! FEED F3 /5 j FEED F3 3 SHORT 5 9 LONG 16 20 A/EEDLES NEEDLES I3 77 2: I4 is 22 FIG. 5 a

BYM M' a ATTORNEYS Feb. 23, 1971 RQ AIGENBAUM ETAL 3,564,871

KNIT TUBULAR FABRIC, METHOD AND APPARATUS FOR MAKING SAME Filed April 4, 1968 4 SheetS -Sheet 4 w A I Q g Q 8 Q 6 M A v g g a Z Q s 2 E 2 3 F I Y INVENTORST ROY u FAIGENBAUM JOHN GRECZIN ATTORNEY.

3,564,871 KNIT TUBULAR FABRIC, METHOD AND APPARATUS FOR MAKING THE SAME Roy D. Faigenbaum and John Greczin, both of 7312 School Lane, Melrose Park, Pa. 19126 Filed Apr. 4, 1968, Ser. No. 718,680 Int. Cl. D04b 9/44 US. Cl. 66-9 1 Claim ABSTRACT OF THE DISCLOSURE A circular knitting machine having four feeds; a pair of yarn guides for each feed, for feeding a pair of separated yarns at said feed, means causing alternate needles to pass between the yarns of each pair of yarn guides and causing intermediate needles to engage and knit said yarns to form a double yarn stitch, said alternate needles casting off, un-knit, the yarn from a first yarn of another pair of yarn guides and floating the second yarn of said other pair of yarn guides.

THE BACKGROUND In order to achieve the necessary burst strength, it has been heretofore the practice to use yarns of from one to two thousand deniers in a knit tubular fabric used as a hose covering. But, the heavier the yarn, the larger the nodules which are formed at the intersections of the yarns and, since in use, the hose is dragged around over more or less rough surfaces, the projecting nodules wear out relatively quickly and the entire hose has to be discarded, prematurely. Further, in applications where the feel and appearance must be considered, such as a vacuum cleaner hose, a covering formed of such heavy denier yarns is undesirable, and this accounts for the practice of covering a vacuum cleaner hose and the like, with a braided fabric which is considerably more expensive than its knit counterpart.

THE INVENTION The invention is carried out on a circular, single cylinder knitting machine having multiple feeds; two yarn guides for each feed; a number of short needles; an equal number of long needles which alternate with the short needles, an upper cam track for actuating the short needles, and a lower cam track for actuating the long needles. It will be understood that the needle cylinder is stationary and that the cam tracks and the yarn guides rotate about the axis of the cylinder. It will also be understood that the needles used are of the offset type shown in Larkin Pat. No. 2,201,905.

In a successfully operated prototype, there were four feeds located at 90 centers; sixteen short needles which alternated with sixteen long needles, and eight yarn guides located at 45 centers, so that two yarns are delivered at each feed.

In the drawing:

FIG. 1 is a developed view diagrammatically illustrating the relation of the needles to the feeds, to the yarn guides, and to the cam tracks.

FIG. 2 is a top plan view of the needle stem and shows the angular relation of the yarn guides to each other and to the needle slots.

FIGS. 3 to 6 inclusive, show the knitting steps which take place at each of the four feeds F1, F3, F2, F4, respectively.

FIG. 7 shows the back side fabric produced by the machine and method of this invention.

FIG. 1 shows sixteen short needles: 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29 and 31; and sixteen long needles: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30 and 32, for a total of 32 needles, and four feeds F1,

United States Patent Olhce 3,564,871 Patented Feb. 23, 1971 F2, F3 and F4. It should be noted that these happen to be the numbers of needles and feeds in the commercially operated machine above referred to, and that to knit larger, or smaller, diameter tubes, the number of needles; the offset of the needles, and the diameter of the needle cylinder and of the needle stem can be increased or decreased, as long as the total number of the long and short needles continues to be a multiple of two, and as long as two spaced yarns are fed at each feed. As shown in FIG. 2, there are eight yarn guides, G1 to G8, for delivering yarns Y1 to Y8, or two separate yarns at each feed.

FIG. 1 also shows an upper cam track C1 for receiving the butts B1 of the short needles S, and a lower cam track C2 for receiving the butts B2 of the long needles L where- 'by, upon rotation of the tracks the lower cam will raise and lower the long and the upper cam will raise and lower the short needles. It is to be noted that the distance between the lower and the upper tracks is equal to the difference in the lengths of the needles, so that the hooks of all of the needles will have the same range of movement.

It will also be noted that upper cam track C1 has two elevated horizontal dwells D-1 and D2 and two intermediate V-shaped depressions V1 and V2, and that lower cam track C2 has dwells D3 and D4 and depressions V3 and V-4 which are similar, but which are disposed oppositely to, the dwells and depressions of cam track C1. See FIG. 1.

By this arrangement, the short needles will be raised to latch clearing level to take yarn and knit at feeds F1 and F3, while the long needles are raised to latch clearing level and traverse these two feeds at said raised level. Conversely, the long needles are raised to latch clearing level to take and knit at feeds F2 and F4 while the short needles are raised to latch clearing level and traverse these two feeds at said level.

As is best shown in FIGS. 1 and 2, there are eight yarn guides, two to each feed, so that two yarns are fed at each feed. It will be noted that the yarn guides are so spaced (45) that the yarns from each pair of guides diverge into a V-shaped path which begins at the knit point. See yarns Y1 and Y2 at feed 1, FIG. 1, for example. It will be noted that needles which are raised to the position of needles L at feed F1, FIG. 1, and which are moved past a feed, will pass between and split the yarns at that feed with one yarn (Y1) at the back and with the other yarn (Y2) at the front of the needle and below the latch thereof. See needle 4 in FIG. 3. While this is going on, yarns Y1 and Y2 are being taken and knit by the short needles S. See needle 3, FIG. 3. Thus, at each feed, one set of needles is raised and passes the feed at such raised level to split the yarns while the other set of needles knits the said pair of yarns at such feed. From the drawings, it will be seen that short needles knit yarns Y1 and Y2 at feed F1. (FIG. 3) and knit yarns Y5 and Y6 at feed F3 (FIG. 5), while the long needles L, knit yarns Y3 and Y4 at feed F2 (FIG. 4) and knit yarns Y7 andY8 at feed F4. It will also be seen that short needles S split yarns Y3 and Y4 at feed F4 (FIG. 4), and split yarns Y7 and Y8 at feed F2 (FIG. 6), while the long needles L split yarns Y1 and Y2 at feed F1 (FIG. 3) and split yarns Y5 and Y6 at feed F3 (FIG. 5). Since each needle knits two yarns at each feed, it will have two stitches on its shank below its open latch. Therefore, when a needle is raised to split the yarns at the following feed, (where it does not knit), it will have one float, Y1, behind it, (FIG. 3) and one float, Y2, in front of it and below its latch (FIG. 3). In other words, as each needle knits, it will have three yarns below its open latch (two stitches and the float in front of the needle), all of which are cast off during the knitting of another pair of yarns. Obviously, the front yarn is cast off un-knit, and appears as the diagonally disposed yarn at 2a, 4a, 6a and 8a, in FIG. 7. Inspection of FIGS. 3 to 6 shows that front float yarn Y2 is cast off with stitches of yarn Y7, Y8, on needles L, FIG. 4; the front float of yarn Y4 is cast off with stitches of yarns Y1 and Y2 on short needles S, FIG. the front float of yarn Y6 is cast off with stitches of yarns Y3 and Y4 on long needles L, FIG. 6, and the front float of yarn Y8 is cast off with stitches of yarns Y5 and Y6 on short needles S, FIG. 3. On being cast off, the float in front of the needle assumes the shape shown at 2a, 4a, 6a and 8a, in FIG. 7. This shape is suggestive of a tuck stitch without, in fact, being one, and, for want of a better name, this formation is referred to as a false tuck stitch.

It will be clear therefore, that the short needles S knit the yarns Y1, Y2, and Y5, Y6, in FIGS. 3 and 5, respectively, and split the yarns Y3, Y4, and Y7, Y8, in FIGS. 4 and 6, respectively; and that the needles L do just the opposite, that is, they knit yarns Y3, Y4, and Y7, Y8, in FIGS. 4 and 6, respectively; and split yarns Y1 and Y2 (FIG. 3) and yarns Y5 and Y6 (FIG. 5), respectively. While the knitting needles cast off the float on the front of the needle un-knit, the float on the rear of the needle floats across the fabric as indicated at 1a, 3a, 5a and 7a, in FIG. 7.

For lack of space, the prefix Y has been omitted from the reference numerals in FIG. 7.

As can be seen from FIG. 7, the front floats which are cast off un-knit, assume the general shape of the stitches with which they were cast off, while the rear floats appear as generally straight lines across the corresponding plain stitch. See 5a in the same FIG. 7.

'It is known that a knotted, or sharply bent, or creased, synthetic yarn loses a large measure of the tensile strength it possesses when in the linear state. Therefore, a tubular cover formed of loops or chain stitches exclusively, will havea relatively low burst strength, and a similar cover which includes the only slightly distorted tuck stitches and the even less distorted tuck stitches and the even less distorted floats, will possess a greater burst strength. It also will be noted that the floats are relatively short and closely spaced and that they are stretched taut against their respective wales. This makes for a firm and smooth texture which has the advantages of braided fabric and is less expensive to make. In the manufacture of a hose covering according to this invention, the hose is pulled upwardly, and therefore the surface of the tubular fabric which would otherwise be the inner surface becomes the outer surface of the fabric, and vice versa. This means that the floats will be on the exterior and the tuck stitches will be on the interior of the tubular fabric.

What -we claim is:

1. A circular four feed knitting machine including:

a needle cylinder,

a first set of short needles movable vertically on said cylinder,

an upper cam track for engaging the butts of said short needles,

a second set of long needles alternating with said short needles and movable vertically on said cylinder,

a lower cam track for engaging the butts of said long needles,

the distance between said tracks being equal to the difference in the length of the needles so that the hooks of both sets of needles will move up and down to the same extent,

pairs of circumferentially spaced yarn guides, one pair for each feed for delivering two separated yarns to said feed,

said pairs of guides being so 'angularly related that, upon movement of the needles to their upper, latch-clearing position, alternate needles pass between two yarns from a first pair of yarn guides, and intermediate needles engage said yarns and knit them to form a stitch connected to a stitch previously made of two yarns from a second pair of yarn guides, said intermediate needles also casting off, un-knit, the yarn from one of a third pair of yarn guides and floating the yarn from the other of said third pair of yarn guides,

said upper cam track having at least two substantially horizontal, raised dwells separated by substantially V-shaped depressions,

said lower cam track having at least two substantially horizontal raised dwells which align with the depressions of the upper track,

said lower track also having substantially V-shaped depressions which align with the dwells of the upper track, and

means rotating said yarn guides and said cam tracks relative to said cylinder.

References Cited UNITED STATES PATENTS 58,610 10/1866 Dalton 6612 3,071,950 1/1963 Chaney 66169(A)X 3,201,954 8/1965 Greczin 66-9(A) 3,212,297 10/1965 Matthews et al. 66198X 3,212,299 10/1965 Frederick 66198X 3,319,440 5/1967 Nebel et al. 66-169(A) 3,457,734 7/1969 Millar 6649 FOREIGN PATENTS 796,727 6/ 1958 Great Britain 661 69 (A) WM. CARTER REYNOLDS, Primary Examiner U.S. C1. X.R. 

